X-ray metrology with diffractors

Abstract

An electron probe microanalysis (EPMA) system includes a graded multilayer diffractor for tightly focusing output x-rays onto an x-ray detector. The graded multilayer construction of the diffractor allows a high x-ray flux to be generated in a small measurement spot, which results in a high measurement throughput. The enhanced measurement efficiency provided by the graded multilayer diffractor can allow an EPMA system to be used as an in-line monitoring tool. The graded multilayer diffractor can include multiple reflecting surfaces. Multiple graded multilayer diffractors can also be used.

1. A method for processing a set of wafers comprising:
 performing a first process on the set of wafers to create a processed set of wafers; 
 performing an inline analysis on at least one wafer of the processed set of wafers by focusing output x-rays from the wafer onto an x-ray detector using a graded multilayer diffractor; and 
 performing a second process on the processed set of wafers after performing the inline analysis. 
 
   
   
     2. The method of  claim 1 , further including directing a probe beam at the wafer to generate the output x-rays. 
   
   
     3. The method of  claim 2 , wherein the probe beam is one of an e-beam and an x-ray beam. 
   
   
     4. The method of  claim 1 , wherein performing the inline analysis includes focusing different sets of output x-rays with different wavelengths using a set of graded multilayer diffractors. 
   
   
     5. The method of  claim 4 , wherein each graded multilayer diffractor is configured to measure a predetermined element x-ray. 
   
   
     6. An x-ray analysis metrology system for analyzing a test sample, the x-ray analysis metrology system comprising:
 a probe beam source for directing a probe beam onto the test sample; 
 a graded multilayer diffractor for focusing output x-rays from the test sample; and 
 an x-ray detector for capturing the focused output x-rays, 
 wherein the graded multilayer diffractor facilitates inline analysis of production wafers. 
 
   
   
     7. The x-ray analysis metrology system of  claim 6 , wherein the probe beam source is one of an e-beam source and an x-ray beam source. 
   
   
     8. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor includes a set of graded multilayer diffractors and the x-ray detector includes a set of x-ray detectors, thereby allowing simultaneous measurement of different elements within the test sample. 
   
   
     9. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is symmetrical in shape. 
   
   
     10. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is asymmetrical in shape. 
   
   
     11. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is cylindrical in shape. 
   
   
     12. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is spherical in shape. 
   
   
     13. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is paraboloidal in shape. 
   
   
     14. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is toroidal in shape. 
   
   
     15. The x-ray analysis metrology system of  claim 6 , wherein the graded multilayer diffractor is ellipsoidal in shape.